Trading off security in a service oriented architecture

Abstract

Service oriented architectures provide a simple yet flexible model of a computing system as a graph of services making requests and providing results to each other. In this paper we define a formal model of a service oriented architecture and using it, we define metrics for performance, for availability, and for various security properties. These metrics serve as the basis for expressing the business requirements. To make trade-offs possible we also define a set of cost metrics, denominated in a uniform currency, to measure the cost of not meeting a requirement. The model, the property metrics, and the cost metrics are then used to generate a Constraint Satisfaction Problem where the objective function is set to minimize the aggregate system cost. We have written these constraints and defined realistic requirements in OPL and we have used them to generate system configurations that minimize the overall cost by optimally trading off the business requirements. © IFIP International Federation for Information Processing 2005.